The American Lindsey Vonn suffered a serious crash in the women's super-G on the opening day of the alpine skiing world championships in Schladming on Tuesday.

The American, a four-times overall World Cup champion, lost balance on her right leg while landing after a jump. Her ski came off immediately, and Vonn slid off course and hit a gate before coming to a standstill, apparently hurting her right knee.

The Austrian federation president Peter Schroecksnadel said doctors told him that Vonn tore her cruciate and lateral ligaments. Schroecksnadel said: "That's the only injury she has, nothing besides this."

Vonn received medical treatment on the slope for 12 minutes before being taken to hospital in a helicopter. The crash came almost exactly one year before the start of the 2014 Winter Olympics in Sochi, Russia.

A statement on the US Ski Team's official website said: "She will be out for the remainder of this season but is expected to return to racing for the 2013-14 Audi FIS World Cup season and the 2014 Olympic Winter Games in Sochi."

Vonn returned to the circuit last month after taking an almost month-long break from racing to recover fully from an intestinal illness that put her in a hospital for two days in November.

Vonn trailed Tina Maze of Slovenia, who won gold, by 0.12 seconds shortly before the crash.

The race, which was postponed for three hours because of fog, continued after another 15-minute delay. Several racers struggled with the conditions. "It's not a very difficult course but in some parts you couldn't see anything," Fabienne Suter of Switzerland said.